1. Field of the Invention
The present invention relates to ordnance mounting assemblies and, more particularly, to a mounting assembly for attachment to a helicopter floor to provide a stable mount for a machine gun or other weapon system, and to increase the weapon system""s field of fire by positioning all or most of the weapon system outside of the helicopter""s cabin.
2. Description of the Background
The utility of a weapon system is largely proportional to the extent of its field of fire. The field of fire can be limited by certain physical attributes of the system itself, for example, the manner in which it is mounted or supported, and/or the type of vehicle used to transport the weapon system. One vehicle that introduces significant limitations is the helicopter. The field of fire for a helicopter-based weapon system is severely limited by the presence of the main rotor overhead and the secondary rotor positioned on the tail. Thus, the field of fire is primarily directed downward and/or forward. Moreover, if the weapon system is mounted within the helicopter""s cabin it may experience additional limitations on its field of fire due to the dimensions of the opening through which it is fired.
The challenge of maximizing the effective field of fire of a helicopter-based weapon system therefore became an issue of positioning all or most of the device outside of the helicopter""s cabin. The present inventor is not the first to devise means for mounting a weapon system external to a helicopter""s cabin.
There are several examples in this regard.
For example, U.S. Pat. No. 5,421,239 to Sanderson discloses an aircraft armament mounting system that includes an elongated support plank member which is longitudinally insertable transversely through the aircraft cabin area so that a central portion of the plank is disposed within the cabin area with opposite end portions of the plank projecting outwardly from the aircraft. The central plank portion is suitably anchored within the cabin area, and the outwardly projecting plank end portions are configured to removably support machine guns supplied with belted ammunition from magazine boxes secured to the top side of the central plank portion within the cabin area.
U.S. Pat. No. 5,767,436 to Sanderson et al. discloses an elongated support plank structure that longitudinally extends transversely through the cabin area of a helicopter and has outer end portions projecting outwardly beyond opposite sides of the helicopter. A pair of 30 mm. machine guns are mounted on the plank end portions and are supplied with belted ammunition from magazine boxes mounted on the plank within the cabin area. The 30 mm. machine guns are secured to the outer plank end portions by specially designed mounting structures each having a cradle portion with axis-adjustable roller assemblies that engage the gun and essentially preclude lateral movement thereof relative to the cradle, but permit roller-guided longitudinal gun recoil movement, during firing of the gun. The field of fire provided by this mounting structure is fixed essentially forward in the direction of the helicopter""s flight path, and the lightweight, M230 30 mm. machine guns do not possess the same capabilities (e.g. firepower) of larger, heavier MK44 systems.
U.S. Pat. No. 6,250,197 to Sanderson discloses a machine gun and associated armament apparatus including an ammunition box for supplying belted ammunition to the gun. The gun and associated apparatus are exteriorly supported on a landing gear sponson tow plate of a helicopter, adjacent a cabin area gunner""s window, using a specially designed pintle support structure. The external mounting of the gun and associated armament apparatus frees up cabin space and permits the gunner""s window to be closed with the gun in a ready position.
While each of the prior art devices detailed above provides an ability to mount all or most of a weapon system outside of a helicopter""s cabin, thereby increasing the weapon""s field of fire, they are meant to accommodate only relatively small, lightweight weapon systems (e.g. small caliber machine guns, weapons not requiring mounting turrets). The installation of larger, heavier weapon systems (e.g. chain guns with stabilized turret systems) in a helicopter raises the additional issue of preserving the in-flight stability of the aircraft. To the best of the knowledge of the present inventor, a mounting assembly (i.e. an interface pallet) for positioning all or most of a large, heavy weapon system external to a helicopter""s cabin does not exist.
It would, therefore, be greatly advantageous to provide an interface pallet assembly that, in addition to positioning all or most of a weapon system outside of the helicopter""s cabin, in order to increase its field of fire, is designed to accommodate a large, heavy weapon inclusive of a stabilized turret. An apparatus for this purpose must preserve the in-flight stability of the aircraft. It should also utilize existing points of connection to the helicopter""s deck, be fabricated of materials with high strength-to-weight ratios, and provide a storage or mounting location for accessories associated with the weapon system.
It is, therefore, an object of the present invention to provide an interface pallet assembly for positioning all or most of a large, heavy weapon system external to a helicopter""s cabin in order to increase its field of fire.
It is another object of the present invention to provide an improved interface pallet assembly that extends a helicopter-based weapon system""s downwardly-angled field of fire without negatively impacting its azimuth rotation capability, thereby allowing the weapon system to be used for helicopter-based airborne mine clearance missions.
Yet another object of the present invention is to provide an improved interface pallet assembly that preserves the in-flight stability of the helicopter by equally distributing the forces associated with the weight and recoil of the weapon system to the deck of the aircraft.
It is still another object of the present invention to provide an improved interface pallet assembly that is fabricated of materials with high strength-to-weight ratios so as to not unduly add to the overall weight of the helicopter and its payload.
It is another object of the present invention is to provide an improved interface pallet assembly as described above that attaches to existing points of connection on the helicopter""s deck.
Still another object of the present invention is to provide an improved interface pallet assembly that includes storage or mounting locations for accessories associated with the weapon system (e.g. ammunition canisters, batteries).
According to the present invention, the above-described and other objects are accomplished by an interface pallet assembly for use between the cabin deck of a helicopter (e.g. the MH60S helicopter) and a large, heavy weapon system (e.g. the stabilized turret system and deck-mounted MK44 30 mm. chain gun). The present invention generally incorporates a platform including a cantilevered pallet mounted inside the helicopter and extending downward at an angle to a turret plate external to one side of the helicopter""s cabin, to which the weapon system""s stabilized turret is attached. In addition, a truss assembly maintains appropriate ground clearance while supporting the platform. The one-sided design of the present invention allows the other side of the helicopter""s cabin to be utilized for activities such as search and rescue missions (i.e. the deployment of a winch to lift/lower personnel, equipment, and/or supplies to/from the helicopter).
The existing deck connection points (e.g. five cargo tie-down locations in the MH60S helicopter) are utilized to secure the interface pallet assembly to the cabin deck. The five-point connection pattern between the interface pallet assembly and the MH60S helicopter deck maintains the overall balance of the airframe by providing for the even distribution of the weight and recoil forces associated with the MK 44 weapon system (i.e. a maximum load of 15,000 pounds at any single tie-down location). The interface pallet assembly adds 20E to the downward angle of fire of the weapon system and also provides for azimuth rotation of 180E. The present invention possesses a significant degree of rotational stiffness (i.e. 250,000-480,000 Newton-meters/radian, depending upon the materials of construction). Sufficient rotational stiffness is required by the aforementioned turret stabilization system to maintain the firing accuracy of the MK 44""s full impulse round during burst mode firing sequences. The interface pallet assembly is fabricated of a variety of materials with high strength-to-weight ratios so as to not unduly add to the overall weight of the helicopter and its payload, and provides storage or mounting locations for a 200-round ammunition container and the battery system that powers the turret and weapon system.